Spiral gear



Oct. 11, 1932. s. J. SANFORD 1,332,302

SPIRAL GEAR Filed March 13, 1929 2 Sheets-Sheet 1 K3 t -A' M/VEWTOR lV/IWESS. L

. Had/:7 J arvoro Oct. 11, 1932. I 5, SANFORD 1,882,302

"' V SPIRAL GEAR Filed March 15; 1929 2 Sheets-Sheet 2v 7' Avi a M705 W/r/m'ss: I I a (fall ora izrw 7 @y f S 014/ W3 Armiyax gear constructed according to my invention Patented Oct. 11, 1932 UNITED STATES PATENT OFFICE SYDNEY J'. SANFOBD, OI ALDEN PARK MANOR, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO CHESTER W. LABNER, 0F PHILADELPHIA, PENNSYLVANIA SPIRAL cnan Application filed larch 13, 1929. Serial No. 346,545.

disk of the device with relation to the recording or reproducing needle 'will be uniform during the travel of thenee dle over the dlSk. At present the sound recording or reproducing disks are rotated at a speed constant or nearly so. For this reason the linear travel of the disk relative to the needle is much more rapid when the needle'is traveling near the outer edge of the disk than whenv the needle is traveling near the center of the disk. By driving the disk at a uniform rate of travel relative to the needle the most suitable speed for reproduction may be used. Moreover, the size of the disk possible to use is no longer limited by the speed permissible at the outer edge. Also it is possible to record much more sound on a disk of the same size when it is driven at a constant travel relative to the needle.

When producing a master record on a disk. a constant travel relative to the needle will give a much more even product for the reason that the needle sinks in the wax recording medium to a greater depth at a* slow travel than it does at a higher travel, while a constant travel keeps the needle at a uniform depth, which will therefore produce a more even sound.

These advantages are particularly important in sound recording and reproducing machines used in synchronization with moving picture films.

For a more complete disclosure of my invention reference may be had to the annexed drawings and'specification at the end whereof my invention will be pointed out and claimed.

In-the drawings,

Figure 1 represents a front elevation of a thereon.

and adapted for use with the turntable of a sound recording or reproducing machine.

Figure 2 is a side elevation with parts of. the gear in Figure 1 omitted showing the gearing between the spiral gear and the turntable. I

Figure 3 is a partial cross section on line 3 3 of Figure 1.

Figure J: is a cross section showing an alternative arrangement of the disk. 1

Figure fi is a modified pinion to cooperate with the modified disk shown in Fig. 4.

Figure 6 is a diagrammatic view of a disk having a modified form ofspiral.

Spiral gears constructed according to my invention consist of a disk 1 havin on one surface thereof a spiral rack 2 consisting of one or more coils arranged in a path or track.

As shown in Figure 6, the inner and outer coils ma; be circular thus providing for overtravel at either end of the operation of the device. v

Between each coil of the spiral rack there may be placed a partition member 3, as shown in Fig. 3, or a groove 25, as shown in Fig. 4, these partitions or grooves being utilized to guide the pinion 5. Gear teeth 4 are cut or arranged so as 'to form the rack 2. These gear teeth may be provided in any manner suitable.

The spiral rack may beformed by moulding the gear teeth on the surface of the disk 2 or by stamping the gear teeth onto the disk or in any other suitable manner.

Forty-four (44) represents the driving shaft which is adapted to be driven from any suitable source of power. Gear 5 which may be of cylindrical or slightly beveled shape to mesh with gears 4, is 'slidably mounted, on shaft 44 and is driven thereby by means of spline 6.

In the modification shown in Figures 4 and 5, the pinion 5 has a flange 66 to cooperate with the guide grooves 25'in'the disk 1.

Disk 1 is carried on shaft 7 -mounted in bearings 8 and 9. Shaft 7 carries collars 10 I Cooperating with collars 1O is'fork 11 pivotally mounted in bearings 12. At one J end. of fork 11 is mounted lever arm 14 having a pin 15- mounted thereon. Spring pressed latch 16 operates to hold lever 14 in position so that rack 2 is meshed with gear 5.

Bearings 8 and 9 are supported by legs 17 which also carry bell crank lever 18 which has at the end of one arm weight 19 so arranged that the other arm 20 bears against gear 5 and tends to move it towards the center of disk 1 when gear 5 and rack 2 are not in mesh.

Disk 1 carries at the peripheral edge thereof a spur gear 21 driving pinion 22 which, in turn, drives bevel gears 23 from which is driven the turntable 24 of the sound recording or reproducing device.

In operation, pinion 5 starts to mesh with rack 2 on disk 1 at the inner coil of the spiral as does the recording or'reproducing needle on the sound recording disk 56 which is adapted to be carried by turntable 24. Upon starting to record or reproduce sound, power is supplied to shaft 44 which thereupon drives disk 1 through pinion 5 and rack 2. Pinion 5 moves outward guided by partitions 3, as shown in Fig. 3, or by grooves, as shown in Fig. 4, keeping. proportionately the same radial distance from the center of disk 1 as the recording needle maintains from the center of turntable 24. Shaft 44 is driven at constant speed.

The ratio of the radial travel of pinion to the radial travel of the needle .is a constant. The turntable 24 and consequently the disk carried thereby are turned at a constant linear travel relative to th needle.

The above embodiment is merely one form of my invention and I do not intend to be limited in the practice of it save by the scope of the attached claims.

' I claim: I

1. A gear comprising a disk having an element protruding from one surface thereof which divides the surface into a spiral path or track and another element arranged in the spiral path or track to provide gear teeth therein.

2. A variable speed device comprising the combination of a shaft axially slidable but radially fixed. a disk mounted thereon having a path or track with gear teeth therein spirally arranged on the surface of the disk, collars mounted on the shaft, a fork to cooperate with the collars, a lever to shift the fork, a second.

shaft, :1 gear slidably but non-rotatably mounted thereon and adapted to mesh with the gear teeth in the spiral path or track on the disk, and automatic means for moving said gear radially of said disk when said gear is not in contact with said disk.

3. A variable speed device comprising in v combination a shaft/mounted 1n bearings so as to be axially slidable but radially stationary, a gear fastened thereto comprising a disk having a spiral path or track with gear teeth therein on the surface of the disk, collars mounted on the shaft, a fork to cooperate with the collars to shift the shaft, a lever adapted to actuate the fork, a spring pressed latch adapted to retain the lever in one extreme position, a second shaft, a gear slidably but non-rotatably mounted thereon so as to mesh with the gear teeth in the spiral path or track on the disk, and automatic means for 'moving said second gear axially of the shaft when said first gear is moved, out of mesh with said second gear.

of the disk, a driving shaft, a gear driven by said shaft and adapted to mesh with the gears in the path or track on said disk, means pro-' viding relative radial movement between said gear and said disk, a turntable for carrying a sound recording disk, and gearing connecting the disk carrying the spiral path or track with the turntable.

5. A revolvable turntable for sound recording records, a shaft rotated at a constant speed and connections between said turntable and shaft whereby the former is rotated at a uniformly increasing or decreasing rate said connection including a gear mounted so as to be axially slidable but radially fixed and having teeth thereon arranged in a spiral pat 6. A gear comprising a disk having teeth thereon arranged in two continuous paths of different lengths and teeth arranged in a spiral path connecting at its ends with said continuous paths.

7. A gear comprising a disk having teeth thereon arranged in two circles of different diameters and teeth arranged in a spiral path connecting at its ends with, said circles.

8. A gear comprising a disk having teeth thereon arranged in a spiral path and partitions or walls arranged between the adjacent turns of the spiral.

9. In a mechanism for rotating a sound recording or reproducing disk, the combination of a driving element rotating at constant speed and axially movable. a driven element connected to said driving element by toothed gearing, means wherebv said driven element may be rotated on a fixed center at a uniformly increasing or decreasing angular speed. a turntable for said disk driven by said first mentioned driven element, means whereby said turntable is driven at a speed in excess of the speed of said driven element, and

means for restoring said driving element by axial movement to starting position.

10. In a mechanism for rotating a sound recording or reproducing disk, the combination of a driving gear rotating at a constant speed, a. driven gear comprising a disk having on one surface gear teeth arranged in a splral path into which the driving gear meshes so that said driven gear is rotated at a uniformly increasing or decreasing angular speed, a turntable for said sound disk driven by said driven gear, and gearing interposed between said driven gear and said turntable.

11. In a mechanism for rotating a sound recording or reproducing disk, the combination of a driving shaft rotating at a constant speed, a driving gear non-rotatably mounted but axially slidable on said driving shaft, a driven gear comprising a disk having teeth arranged in a spiral path meshing with said driving gear whereby said driven gear is rotated at a uniformly increasing or decreasing angular speed, a turntable for said sound disk driven by said driven gear, and gearing interposed between said turntable and said driven gear.

12. A mechanism for rotating a sound recording or reproducing disk according to claim 11 in which there is provided means for moving said driving gear radially of said driven gear.

13. In a mechanism for rotating a sound recording or reproducing disk, the combination of a driving shaft rotating at a constant speed, a driving gear non-rotatably mounted and axially slidable on said driving shaft, a driven gear having teeth thereon arranged in a spiral path and meshing with said driving gear, means for separating said driving and said driven gears, means for moving said driving gear axially of said driving shaft when said driving gear and said driven gear are separated, a turntable for said sound disk driven by said driven gear at a uniformly increasing or decreasing speed, and gearing interposed between said driven gear and said turntable.

14. In a mechanism for rotating a sound recording or reproducing disk, the combination ofa driving gear rotating at a constant speed, a driven gear having teeth mounted in a spiral path and meshing with said driving gear and having a second set of teeth thereon, a turntable for said sound disk driven from said driven gear, and gearing meshing with said second set of teeth on said driven gear for driving said turntable from said driven gear at a uniformly increasing or decreasing angular speed.

SYDNEY J. SANFORD. 

